The trio of the CPU, Attack Node, and Defense Node are actually quite simple if you go about things the right way. If you don't, the CPU will cast Globe 199 on one character at a time, killing them instantly. So you can differentiate between the two Nodes (which otherwise look identical), the one that heals is the Defense Node, the one that attacks is the Attack Node (or quite simply, the Defense Node is at the bottom of the screen, the Attack Node towards the top). First and foremost, kill the Defense Node; it should take no more than a physical attack from Edge and Cecil each to dispatch it. This will eliminate the enemy being able to heal itself. Thereafter, DO NOT attack the Attack Node. Instead, concentrate physical attacks exclusively on the CPU (stay away from summons and magical attacks, as one of the first things the CPU does is cast Reflect on itself). It'll take some patience, but lay into the CPU with all five characters physically attacking. When it's finally dispatched, THEN take care of the Attack Node.